Adjacency Pact

Two countries can agree on exactly where their border lies and still be at each other's throats over everything that crosses it. A river that irrigates one nation's fields after leaving the other's dams. Cattle that wander. Smoke from a neighbor's burning peatland that shuts down airports three countries away. This is the terrain of the adjacency pact — not a formal category in international law, but a useful shorthand for the dense web of arrangements neighbors build to manage the fact of being neighbors.

The distinction from a boundary treaty is the key one to hold. A boundary treaty draws the line; an adjacency pact governs life along a line already drawn. The 1960 Indus Waters Treaty is the classic case: India and Pakistan have fought three wars since signing it, yet the treaty's mechanism for allocating the Indus basin's rivers has largely survived, brokered originally by the World Bank. The 1909 Boundary Waters Treaty between the United States and Canada created the International Joint Commission, still adjudicating Great Lakes and cross-border river disputes over a century later. Schengen, in a very different register, is an adjacency arrangement scaled up to a continent — abolishing internal checks while pooling control of the external frontier.

The subject matter clusters predictably around whatever the border makes shared or contestable: demarcation upkeep and joint survey commissions; simplified local-traffic and customs regimes for people and goods; shared rivers, aquifers, and fisheries; security cooperation like joint patrols and hot-pursuit rights against smugglers or insurgents; and coordination on wildfires, epidemics, and pollution that ignore the line entirely.

Underneath sits a thin but real legal foundation. The customary principle of good neighborliness echoes in Article 74 of the UN Charter, and the duty not to let your territory be used to harm a neighbor was crystallized in two landmark rulings: the Trail Smelter arbitration (1938–41), where a Canadian smelter's fumes damaging Washington State farms produced the principle that no state may use its territory to injure another, and the ICJ's Corfu Channel judgment (1949). These are the load-bearing precedents any delegate arguing a transboundary harm case will reach for.

What makes the concept worth naming at all is that it flags a governance gap. Multilateral instruments are built for problems that scale globally — climate, trade, non-proliferation. But a haze crisis between Indonesia and Singapore, or a disputed grazing corridor in the Sahel, is stubbornly local, and global regimes handle it poorly. Regional bodies sometimes step in — the African Union Border Programme, ASEAN's transboundary haze agreement — but the workhorse remains the bilateral deal between two governments who have no choice but to deal with each other. For an MUN delegate, spotting that a resolution's real problem is an adjacency problem, not a global one, is often the sharper insight.